Note the size difference between a full frame sensor—from the Canon EOS 1Ds—on the left, compared to the smaller sized sensor of the earlier EOS D60 on the right.

Probably the dimmest of the viewfinders we’ve used is the Olympus Evolt E-330, which, as we described two issues back, siphons some of its light out of the viewfinder path and redirects it to the Live Viewer imager pickup.

Perhaps astute readers have noticed that Photo Trade News doesn’t have
a “letters to the editor” section. Why that is so is unknown to yours
truly, for the Digital Dude is seldom involved in decisions outside his own pages.
However, if he were, he’d have plenty of good reasons to exclude a “reader’s” page
from the publication.

For starters, according to surveys, 93% of all “reader letters” are
actually composed by industry analysts on the cheap trying to learn what to say
when their clients ask. Another 79% are written to trick the editors and expose
them as being dumber than they think. An additional 83% are by out-of-work freelance
writers, trying to start a relationship. That’s 255% altogether, but
these were very casual surveys.

Don’t get us wrong, we love to hear from readers. And yours truly never
believes surveys. But even real letters go against at least some of the grain
of some publications. Those that have “News” in their titles, for
example, have plenty to report, but few readers’ letters are really “news.” They
may be insightful, cogent, and well-stated, and we may love answering them off-line,
but they’re often about topics that were last issue’s news. They
may all be good questions, but only some have the currency to be published
in Photo Trade News.

Besides “news” in our title, there’s also the “photo
trade” part. A letter that asks how to work a certain camera may be well-suited
for a consumer publication, but the orientation here is different. Our readers
being retailers, they already should know how to work every camera. We may
love discussing that off-line again, but what gets printed for our readers
might have more to do with how to present the camera.

That’s how the thinking would go if the Digital Dude ran things, and there
would be no “letters” page. There would simply be letters, when
and as they come up, which, besides being insightful and cogent and well-stated,
bear also upon newsworthy things of interest to the trade. We receive quite
a few.

It would be immodest for us to publish the sweet nothings some readers send
us, or the cards that come with their bouquets of flowers and boxes of chocolates.
But here are two of another order, perhaps of broader interest.

Seeing the Light

Probably the first thing most customers do when examining a new camera is put
the viewfinder to their eye. This means that their first impression about
working the camera is based upon the viewfinder, how comfortable and practical
it is. That being the bedrock of all subsequent impressions, the seemingly
simple viewfinder plays a surprisingly profound role in making the camera
likeable or otherwise. In this regard, yours truly received the following
e-mail from a reader identified only as Tracy.

“Very interesting article,” states Tracy in response to one recent
camera review. “You are an excellent writer and the historical perspective
you supply is so valuable.” And we promised we’d keep the flowers
and chocolates out of this! But Tracy goes on:
“You mentioned the bright digital SLR viewfinder, and I wonder if I could
get your advice on this topic. My Nikon F2 was just stolen, and I am finally
going to try a digital SLR. I am finding that the viewfinders on the Nikon D70
and the Canon 20D seem a bit dim. I just don’t feel that I am seeing the
shot as well. Any thoughts? Do you think the viewfinder is likely to be improved
in the next iteration of the Nikon prosumer DSLR? I realize you may not have
the time to answer my question, but I thought I’d give it a try.”

For a question like this, we’d make the time to answer. It’s an
important question indeed, as DSLRs sustain their juggernaut rampage across
the photographic landscape. It suggests certain preparations for the demonstration
of a DSLR, if conditions allow. For the through-the-lens viewing of a DSLR,
the viewfinder is obviously influenced by the brightness of the lens. An f/2.8
lens on a given DSLR will create a brighter viewfinder image than an f/4.5
lens on that same camera.

Whether you actually demonstrate the camera with the faster lens, however,
brings some considerations of an ethical nature into the formula. Will the
customer be buying the camera with that particular lens? If so, go for it.
But most of the “kit” lenses offered with the low- and mid-price
DSLRs are more in the f/3.5 range, and the customer buying the kit should evaluate
the package, viewfinder included, with the accompanying lens.

PTN readers are the world’s most ethical, of course, but even the readers
of rival publications should take heed—for where ethics leave off, enlightened
self-interest sometimes kicks in. That is, a customer ought to be satisfied
from the beginning. For most retailers, the cost of losing a sale is still
less than the cost of processing a return.

But the speed of the lens would not be the sole factor in the brightness
of an SLR viewfinder. The viewfinder’s own construction must bring influences
to bear. Tracy mentions the Canon 20D, whose attributes in this regard are
matched by the new 30D. Both models use the same APS-C-size imager, which is
smaller than a 35mm film frame. Would this require a smaller mirror and optical
path? And would this in turn have an effect upon the amount of light transmitted
through it?

We took the question to Canon, for two good reasons. First, they’re the
only manufacturer of DSLRs offering both APS-C and full-frame cameras, so they’re
the most likely to lack a favoritism either way. Second, they have Chuck Westfall
on-hand, whose knowledge of such things is encyclopedic and his willingness
to share quite generous. “Assuming identical lenses,” states Mr.
Westfall, “the two biggest variables in AF SLR viewfinder brightness
are: “1. Prism characteristics: SLRs with glass pentaprisms tend to deliver
brighter images than SLRs with hollow pentaprisms, sometimes called ‘penta-mirrors.’ All
EOS digital SLRs (including the 20D) have glass pentaprisms, except the Rebel
series, which uses pentamirrors. And then there are some SLRs (Olympus comes
to mind) that use roof prisms rather than pentaprisms. These have no particular
advantage or disadvantage when it comes to viewfinder brightness.

“2. Focusing screen characteristics: There’s a lot of variety in
focusing screen design. The old-fashioned ground-glass focusing screens of the
1960s and 1970s have largely been replaced by plastic screens, which are not
only lighter and cheaper, but can also be made much brighter. In fact, by modifying
the surface pattern, brightness can be optimized for specific aperture ranges.
Standard focusing screens for consumer-grade digital SLRs tend to be optimized
for consumer-grade zoom lenses that typically feature maximum apertures as small
as f/5.6. But these screens are often difficult to focus manually, especially
away from the center of the picture area. Professional SLRs like the EOS-1 series
can be outfitted with screens that deliver more sharpness, albeit at the expense
of maximum brightness.